I think they mean Ateji/当て字, when they're used phonetically just to represent something as foreign or for style. Like how sushi is 寿司, but the characters have nothing to do with sushi other than the pronunciation.

Of course, these are the exception. Kanji is integral to japanese writing and it's a pain in the ass without them.

I wonder when kanji stop being Chinese characters in the same way that souvenir used by someone speaking English isn't using a French word. Like characters with different variations in Japanese technically aren't used (and weren't ever used) in China, like 誤 vs 誤 (prob won't show up right with the font on here but the Japanese component on the bottom right uses 六 without the top dot and Chinese uses 大). The kana were all derived from kanji as well, so could those be "chinese" characters? The etymology is obviously Chinese in the same way souvenir is French, but what does that really mean?

Dunno, maybe it's mostly semantics, especially when trying to talk about it in English